Aqueous calcium stearate dispersions have long been used as additives in paper coating formulation, the calcium stearate imparting lubricating, leveling and anti-dusting properties to the coating formulation.
Since it is preferable in the paper making industry to use as many predispersed starting materials as possible in preparing various coating formulations, it is advantageous to provide aqueous calcium stearate dispersions having as high a solids content as possible. Such advantages inure in lower shipping costs and introduction of less water into the coating formulation.
However, aqueous calcium stearate dispersions containing much above 50 weight percent solids do not retain desirable rheological properties, i.e., they are quite viscous and difficult to handle and meter.
High solids content calcium stearate compositions having workable viscosities are described in U.S. Pat. Nos. 4,659,489 and 4,676,836. U.S. Pat. No. 4,659,489 discloses high solids content, i.e., 50 to 75 weight percent, aqueous dispersions containing calcium stearate, dispersing agent, non-ionic lubricant and urea. U.S. Pat. No. 4,676,836 describes similar compositions, except that anionic lubricant is used in place of the non-ionic lubricant of U.S. Pat. No. 4,659,489.